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From: kaleb@mars.jpl.nasa.gov (Kaleb Keithley)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Help needed for MFM drive with RLL controller
Keywords: can ST251 be used as RLL?
Message-ID: <2292@jato.Jpl.Nasa.Gov>
Date: 29 Nov 89 21:53:58 GMT
References: <1989Nov29.074452.9386@ug.cs.dal.ca>
Sender: news@jato.Jpl.Nasa.Gov
Reply-To: kaleb@mars.UUCP (Kaleb Keithley)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 42

In article <1989Nov29.074452.9386@ug.cs.dal.ca> walker@ug.cs.dal.ca (Paul D. Walker) writes:
>
>My question is, can a Segate-251 MFM drive be used as an RLL drive?  For
>those that don't know, the ST-251 is a 28ms access, 40 meg hard drive with 
>820 cylinders and 6 heads (type 40).
>

I don't see why not, I have a Micropolis MFM drive with 1024 cyl and 8 heads,
and I did the same thing.  Working fine for over six months now.

>The RLL card that I am trying to use with this drive is a Data Technology
>Corporation (DTC) 7287 RLL Controller card.  
>

Although I have a WD1003 RLL controller.

>	I have tried using the cards on board firmware to format the drive 26
>sectors per track instead of 17.  If I used the standard types table, it is 
>also a type 40 drive.  After the type has been set, my machine is rebooted 
>and the low level format program is run.  Immediately, an error is returned
>and nothing happens.  It seems that the drive does not like any of the 
>commands that the controller sends to it.
>

Western Digital's on board bios set the drive type in CMOS to type 1.  I tried
changing it to other types and got errors; I don't recall the specifics.
When I changed it back to 1, everything worked fine again.

>	I tried to use a program called 'Speedstore which is a 'hard disk
>preparation and maintenance program'.  For a drive type, I tried changing the
>number of sectors from 17 to 26.  When this program tries to format the disk, 
>it comes back with a '01h bad command to bios' message, and then stops.
>

I also ran WD's surface scan, which showed more bad sectors than the bad
sector list shipped with the drive.  Even when I entered the bad sectors
in the map, DOS 4.01's high level format still tried to recover them.

Chewey, get us outta here!
                 
kaleb@mars.jpl.nasa.gov             (818)354-8771
Kaleb Keithley